This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
At 3GPP LTE RAN #69 plenary meeting, a new work item named NB-IOT was approved. Since then the 3GPP organization has been working on solutions for the operation of machine-type communications (MTC) and for NB-IOT (Narrow Band Internet of Things).
The NB-IOT is expected to support up to a 20 dB coverage improvement, a massive number of low throughput devices, low delay sensitivity, ultra-low device cost, low device power consumption, and (e.g., optimized) network structure. Furthermore, NB-IOT bandwidth is only 180 kHz, corresponding to one PRB (and 12 subcarriers) in LTE.
Advantages of NB-IOT can include smart metering for remotely collecting electricity, water and gas meter data over the cellular network. This aspect of the NB-IOT topic is mainly due to the market opportunity it presents. Such smart metering can consequently help cut down cost generated from manual meter reading and changing of meter batteries for example.
The example embodiments of the invention work to optimize random access procedures for NB-IOT such that at least random access failure rates of devices using NB-IOT is reduced or eliminated.
Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:    CE Coverage Enhancement    CP Control Plane    dB Decibels    dBm Decibels milliwatt    eNB Enhanced NodeB    HO Handover    MT Mobile Terminated    MTC Machine-Type Communications    NB-IOT Narrow Band Internet of Things    PRACH packet random access channel    RLF Radio Link Failure    RRC Radio resource control    RSRP Reference Signal Received Power    TX Transmission    UE User Equipment    UP User Plane